Toxoplasma gondii infections are a major source of visual loss and blindnes Ocular toxoplasmosis may occur as a result of congenital infections, acquir infections, and as a manifestation of immunosuppression, particularly as a result of transplantation or acquired immunodeficiency syndrome (AIDS). Due to the recent resurgence of acquired ocular toxoplasmosis in Brazil and the worldwide complications of toxoplasmosis in HIV infections, we initiate studies to develop a model of acquired toxoplasmosis to evaluate the molecular mechanisms of pathogenesis and therapeutic strategies. We have developed a murine model of ocular toxoplasmosis that is characterized by retinal inflammation, chorioretinal scaring, retinal disorganization, and cyst formation. Retinal disease occurs in three differ t strains of mice following inoculation with toxoplasmosis by the subcutaneou or intraperitoneal routes. This model of acquired ocular toxoplasmosis is being used to evaluate the efficacy of new antiparasitic agents in controll g the development of retinal cyst formation and retinal inflammation.